Worldwide fossil fuel resources are rapidly depleting and the harmful effects of their use have been well documented. As a result, there is an ever increasing drive to provide energy, more specifically electricity, from renewable sources in an attempt to reduce further damage to the environment. Renewable sources of energy are varied in their nature, with solar power, wind power, hydroelectric power, geothermal power and wave power all commonly used methods of producing renewable energy. Such devices are well known in the art, for example as described in WO 2013/011318. However, with the majority of renewable sources, the amount of energy it is possible to generate at any one point in time is difficult to control.
It is commonly appreciated that a lack of wind, an overcast day or a lack of waves will negatively impact the ability to generate electricity via renewable sources. In such circumstances it is typical that the renewable source is providing negligible means to generate electricity; for example a hydroelectric flow may be insufficient to turn a water wheel. However, it is less commonly appreciated that wind speeds, wave action or water flow rates may be excessive for power generation. In such circumstances, the high stresses placed on an electrical generator, for example due to the excessive rotational speed of a generator shaft, may result in damage to said generator and other equipment associated with it if electricity generation is not paused.
This dependence on the correct environmental conditions for power generation can result in the sporadic availability of electricity if only a single renewable source is used for power generation. As such any strategy for electricity generation must include either a wide range of renewable sources, to ensure there is always the capacity for energy generation, means to store excess electricity for later use when renewable generation is impossible or backup generation methods in the form of fossil fuel or nuclear power stations. Whilst this is an acceptable solution for electrical supply at the largest scales, for example a national grid, such methods are wholly unsuited to circumstances where there is a desire for the means of electricity generation to be portable or the generation system is required to be remote and thus cannot be supplemented with a backup supply.
The need for a secondary, backup method of power generation or the ability to store electricity can be reduced, and perhaps eliminated, if energy, in the form of electricity, can be generated across a wider range of naturally occurring conditions. Progress in this area would be a benefit to the renewable energy sector, increasing the reliability of the electricity supply in any location without access to a large scale grid.